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Head and neck cancer patient positioning using synthetic CT data in MRI‐only radiation therapy

PURPOSE: The accuracy and precision of patient positioning is crucial in radiotherapy; however, there are no publications available using synthetic computed tomography (sCT) that evaluate rotations in head and neck (H&N) patients positioning or the effect of translation and rotation combined. Th...

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Autores principales: Palmér, Emilia, Nordström, Fredrik, Karlsson, Anna, Petruson, Karin, Ljungberg, Maria, Sohlin, Maja
Formato: Online Artículo Texto
Lenguaje:English
Publicado: John Wiley and Sons Inc. 2022
Materias:
Acceso en línea:https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8992936/
https://www.ncbi.nlm.nih.gov/pubmed/35044070
http://dx.doi.org/10.1002/acm2.13525
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author Palmér, Emilia
Nordström, Fredrik
Karlsson, Anna
Petruson, Karin
Ljungberg, Maria
Sohlin, Maja
author_facet Palmér, Emilia
Nordström, Fredrik
Karlsson, Anna
Petruson, Karin
Ljungberg, Maria
Sohlin, Maja
author_sort Palmér, Emilia
collection PubMed
description PURPOSE: The accuracy and precision of patient positioning is crucial in radiotherapy; however, there are no publications available using synthetic computed tomography (sCT) that evaluate rotations in head and neck (H&N) patients positioning or the effect of translation and rotation combined. The aim of this work was to evaluate the differences between using sCT with the CT for 2D‐ and 3D‐patient positioning in a magnetic resonance imaging (MRI)‐only workflow. METHODS: This study included 14 H&N cancer patients, with generated sCT data (MRI Planner v2.2) and the CT deformably registered to the MRI. Patient positioning was evaluated by comparing sCT against CT data: 3D cone beam CT (CBCT) was registered to the deformed CT (dCT) and sCT in six degrees of freedom (DoF) with a rigid auto‐registration algorithm and bone threshold, and 2D deformed digital reconstructed radiographs (dDRR) and synthetic DRRs (sDRR) were manually registered to orthogonal projections in five DoF by six blinded observers. The difference in displacement in all DoF were calculated for dCT and sCT, as well as for dDRR and sDRR. The interobserver variation was evaluated by separate application of the paired dDRR and sDRR registration matrices to the original coordinates of the planning target volume (PTV) structures and calculation of the Euclidean distance between the corresponding points. The Dice similarity coefficient (DSC) was calculated between dDRR/sDRR‐registered PTVs. RESULTS: The mean difference in patient positioning using CBCT was <0.7 mm and <0.3° and using orthogonal projections <0.4 mm and <0.2° in all directions. The maximum Euclidean distance was 5.1 mm, the corresponding mean (1SD) Euclidean distance and mean DSC were 3.5 ± 0.7 mm and 0.93, respectively. CONCLUSIONS: This study shows that the sCT‐based patient positioning gives a comparable result with that based on CT images, allowing sCT to replace CT as reference for patient treatment positioning.
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spelling pubmed-89929362022-04-13 Head and neck cancer patient positioning using synthetic CT data in MRI‐only radiation therapy Palmér, Emilia Nordström, Fredrik Karlsson, Anna Petruson, Karin Ljungberg, Maria Sohlin, Maja J Appl Clin Med Phys Radiation Oncology Physics PURPOSE: The accuracy and precision of patient positioning is crucial in radiotherapy; however, there are no publications available using synthetic computed tomography (sCT) that evaluate rotations in head and neck (H&N) patients positioning or the effect of translation and rotation combined. The aim of this work was to evaluate the differences between using sCT with the CT for 2D‐ and 3D‐patient positioning in a magnetic resonance imaging (MRI)‐only workflow. METHODS: This study included 14 H&N cancer patients, with generated sCT data (MRI Planner v2.2) and the CT deformably registered to the MRI. Patient positioning was evaluated by comparing sCT against CT data: 3D cone beam CT (CBCT) was registered to the deformed CT (dCT) and sCT in six degrees of freedom (DoF) with a rigid auto‐registration algorithm and bone threshold, and 2D deformed digital reconstructed radiographs (dDRR) and synthetic DRRs (sDRR) were manually registered to orthogonal projections in five DoF by six blinded observers. The difference in displacement in all DoF were calculated for dCT and sCT, as well as for dDRR and sDRR. The interobserver variation was evaluated by separate application of the paired dDRR and sDRR registration matrices to the original coordinates of the planning target volume (PTV) structures and calculation of the Euclidean distance between the corresponding points. The Dice similarity coefficient (DSC) was calculated between dDRR/sDRR‐registered PTVs. RESULTS: The mean difference in patient positioning using CBCT was <0.7 mm and <0.3° and using orthogonal projections <0.4 mm and <0.2° in all directions. The maximum Euclidean distance was 5.1 mm, the corresponding mean (1SD) Euclidean distance and mean DSC were 3.5 ± 0.7 mm and 0.93, respectively. CONCLUSIONS: This study shows that the sCT‐based patient positioning gives a comparable result with that based on CT images, allowing sCT to replace CT as reference for patient treatment positioning. John Wiley and Sons Inc. 2022-01-19 /pmc/articles/PMC8992936/ /pubmed/35044070 http://dx.doi.org/10.1002/acm2.13525 Text en © 2022 The Authors. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, LLC on behalf of The American Association of Physicists in Medicine https://creativecommons.org/licenses/by/4.0/This is an open access article under the terms of the http://creativecommons.org/licenses/by/4.0/ (https://creativecommons.org/licenses/by/4.0/) License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
spellingShingle Radiation Oncology Physics
Palmér, Emilia
Nordström, Fredrik
Karlsson, Anna
Petruson, Karin
Ljungberg, Maria
Sohlin, Maja
Head and neck cancer patient positioning using synthetic CT data in MRI‐only radiation therapy
title Head and neck cancer patient positioning using synthetic CT data in MRI‐only radiation therapy
title_full Head and neck cancer patient positioning using synthetic CT data in MRI‐only radiation therapy
title_fullStr Head and neck cancer patient positioning using synthetic CT data in MRI‐only radiation therapy
title_full_unstemmed Head and neck cancer patient positioning using synthetic CT data in MRI‐only radiation therapy
title_short Head and neck cancer patient positioning using synthetic CT data in MRI‐only radiation therapy
title_sort head and neck cancer patient positioning using synthetic ct data in mri‐only radiation therapy
topic Radiation Oncology Physics
url https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8992936/
https://www.ncbi.nlm.nih.gov/pubmed/35044070
http://dx.doi.org/10.1002/acm2.13525
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